A stationary-type mechanical seal is provided with a pressing mechanism which presses a stationary ring toward a rotating ring. As the pressing mechanism, a technique is known which is configured such that, by respectively providing bellows on an radially outward side and on a radially inward side, an annular sealed space is formed and the bellows are expanded and contracted by controlling fluid pressure inside the sealed space (refer to Patent Literature 1). In a mechanical seal including the pressing mechanism according to this conventional example, bellows are doubly provided on the radially outward side and on the radially inward side. In this case, since a minimum inside diameter on an inner circumferential side of the outer bellows must be set larger than a maximum outside diameter on an outer circumferential side of the inner bellows, a size of the mechanical seal increases in a radial direction.